Some simple methods fail to inline

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#119,510 3 comments 0 reactions 1 assignee View on GitHub

@EgorBo is already working on this.

Since Apr 17, 2026.

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Description

area-CodeGen-coreclr JIT-Inlining

I’ve noticed that some very simple generic methods fail to inline, even though they seem like good candidates. In the example below, SizeOf<T> and AlignedSizeOf<T> are not inlined by the JIT.

While the SizeOf<T> example could potentially be rewritten with a throw helper, it seems like the JIT should be able to do better here without requiring such workarounds.

static uint AlignedSizeOfByte() => AlignedSizeOf<byte>();

static uint AlignedSizeOf<T>() where T : struct
{
    uint size = SizeOf<T>();
    if (size == 1 || size == 2)
    {
        return size;
    }

    return (uint)((size + 3) & (~3));
}

static unsafe uint SizeOf<T>() where T : struct
{
    if (RuntimeHelpers.IsReferenceOrContainsReferences<T>())
        throw new ArgumentException("Argument_NeedStructWithNoRefs");

    return (uint)sizeof(T);
}

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